This invention relates to a wheel for a vehicle, and more particularly relates to a wheel of high accuracy and rigidity, which is for a vehicle and is manufactured less expensively and more efficiently of three separately prepared pieces which are a disk, an inner rim part and an outer rim part.
In recent years, many wheels each made of a light alloy and high in strength, rigidity and dimensional accuracy have been used for motor vehicles along with the enhancement of the performance of the vehicles or that of the performance of the tires thereof. The wheels are formed by casting, forging or the like so that the disks thereof have various shapes to be high in strength and good in exterior view or design. The wheels are classified into three types which are a one-piece type, a two-piece type and a three-piece type. The wheel of the one-piece type is made of a piece monolithically prepared by casting, forging or the like and including a rim and a disk. The wheel of the two-piece type is made of two separately prepared pieces which are a rim and a disk and fixedly conjoined to each other by welding or bolt clamping. The wheel of the three-piece type is made of three separately prepared pieces which are an inner rim, an outer rim and a disk which are fixedly conjoined to each other by welding or bolt clamping.
The constitution of the wheel of the three-piece type, which allows the weight of the wheel to be reduced and is relatively high in rigidity, and the way of assembling the pieces of the wheel are described hereafter. FIG. 4 shows an example 23 of the wheel, which is also called an under-head-type wheel, and includes an inner rim portion 25, an outer rim portion 26, and a disk 24 which are separately formed. The flanges 27 and 28 of the inner and the outer rim portions 25 and 26 are set on each other, and then clamped to the outer design surface of the disk 24 by bolts 11 and nuts 12. The outer circumferential edges of the mutually conjoined surfaces of the flanges 27 and 28 are welded to each other at 10 in order to prevent air from leaking out of a tire 5 fitted on a rim assembly consisting of the inner and the outer rim portions 25 and 26. The disk 24 has a hub hole 13, and four to six bolt holes 14 which are located at equal intervals on a circle concentric to the disk and which each have a circular cross section. The disk 24 is secured to a hub by wheel nuts.
FIG. 5 shows another example 30 of the wheel of the three-piece type, which is also called an overhead-type wheel, and includes an inner rim portion 32, an outer rim portion 33 and a disk 31 which are separately formed. The flanges 34 and 35 of the inner and the outer rim portions 32 and 33 are set on each other, and then clamped to the mounting surfaces of the disk 31 by bolts 11 and nuts 12. The outer circumferential edges of the mutually conjoined surfaces of the flanges 34 and 35 are welded to each other at 10 in order to prevent air from leaking out of a tire 5 fitted on a rim assembly consisting of the rim portions. The disk 31 has a hub hole 13, and four to six bolt holes 14 which are located at equal intervals on a circle concentric to the disk and each have a circular cross section. The disk 31 is secured to a hub by wheel nuts.
FIG. 6 shows yet another example 37 of the wheel of the three-piece type, which is also called a sandwich-type wheel, and includes an inner rim portion 39, an outer rim portion 40 and a disk 38 which are separately formed. The flanges 41 and 42 of the inner and the outer rim portions 39 and 40 are clamped to the sides of the peripheral portion 43 of the disk 38 at the mounting surface and design surface thereof by bolts 11 and nuts 12 so that the flanges pinch the portion. The outer circumferential edges of the mutually conjoined surfaces of the disk 38 and the flanges 41 and 42 are welded to each other at 10 in order to prevent air from leaking out of a tire 5 fitted on a rim assembly consisting of the inner and the outer rim portions 39 and 40. The disk 38 has a hub hole 13, and four to six bolt holes 14 which are located at equal intervals on a circle concentric to the disk and which each have a circular cross section. The disk 38 is secured to a hub by wheel nuts.
Since the flanges 41 and 42 of the inner and outer rim portions 39 and 40 of the sandwich-type wheel 37 pinch the peripheral portion 43 of the disk 38 on both the sides thereof, the wheel needs to have two welding seals 10 for preventing the air from leaking out of the tire 5. For that reason, the wheel 37 requires two times as much welding as the other wheels 23 and 30 of the three-piece type, and is more expensive than them. This is a problem.